Matthew Grevers has won the gold medal in the men's 100m backstroke for the United States.
The American recorded an Olympic record time of 52.16s to edge out compatriot Nick Thoman, who bagged silver.
Ryosuke Irie of Japan came in third and won the bronze with a time of 52.97s, pushing France's Camille Lacourt down to fourth.
Team GB hopeful Liam Tancock could only manage fifth place with his time of 53.35s.
